SIP trunking is a voice over internet protocol (VoIP) and streaming media service by which Internet telephony service providers (ITSPs) deliver telephone services and unified communications to customers equipped with SIP-based private branch exchange (IP-PBX) and unified communications facilities. Unified communications software applications provide voice, video, and other streaming media applications such as desktop sharing, web conferencing, and shared whiteboard.
The architecture of SIP trunking provides a partitioning of the unified communications network into two different domains of expertise: 1) private domain, which is a VoIP solution realized at a customer's home that takes advantage of phone and unified communication services; and 2) public domain, which is a full VoIP access solution to the public switched telephone network (PSTN)/public land mobile network (PLMN) property and responsibility of the ITSP that provides phone service. The interconnection between the two domains must occur through a SIP trunk. The interconnection between the two domains, created by transport via an Internet protocol (IP), involves setting specific rules and regulations as well as the ability to handle some services and protocols that fall into the well-defined name of SIP trunking.
Although the ITSP is responsible to the applicable regulatory authority regarding law obligations of the public domain, the private domain is not subject to particular constraints of law, and may be either the responsibility of the ITSP, the end user (enterprise), or of a third party who provides the voice services to a company. Other contextual information may become further apparent upon review of the following detailed description.